/*
 * Copyright (c) 2019, Systems Group, ETH Zurich
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include "ethernet_frame_padding.hpp"

void ethernet_frame_padding(
  hls::stream<ap_axiu<DATA_WIDTH, 0, 0, 0>>& dataIn,
  hls::stream<ap_axiu<DATA_WIDTH, 0, 0, 0>>& dataOut)
{
#pragma HLS PIPELINE II=1
#pragma HLS INTERFACE ap_ctrl_none port=return

#pragma HLS INTERFACE axis register port=dataIn name=s_axis
#pragma HLS INTERFACE axis register port=dataOut name=m_axis

  static ap_uint<1> state = 0;

  switch(state)
  {
    case 0:
      if (!dataIn.empty())
      {
        ap_axiu<DATA_WIDTH, 0, 0, 0> currWord = dataIn.read();
        if (currWord.last)
        {
          for (int i = 0; i < DATA_WIDTH/8; ++i)
          {
            #pragma HLS UNROLL
            if (currWord.keep[i] == 0)
            {
              currWord.keep[i] = 1;
              currWord.data(i*8+7, i*8) = 0;
            }
          }
        }
        else
        {
          state = 1;
        }
        dataOut.write(currWord);
      }
      break;
    case 1:
      if (!dataIn.empty())
      {
        ap_axiu<DATA_WIDTH, 0, 0, 0> currWord = dataIn.read();
        dataOut.write(currWord);

        if (currWord.last)
        {
          state = 0;
        }
      }
      break;
  } //switch
}